CVE-2026-54900: Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, when in usual mode with create_id enabled, Oj::Parser#parse is vulne

unknownCVE-2026-54900

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, when in usual mode with create_id enabled, Oj::Parser#parse is vulnerable to heap corruption via a negative-size memcpy. When a JSON object key is exactly 65,535 bytes long, an integer truncation in form_attr (usual.c:63) converts the length to -1 before passing it to memcpy. This causes memcpy to copy SIZE_MAX bytes (interpreted as a huge size_t), corrupting heap memory and crashing the process. The issue has been fixed in version 3.17.2.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: unknown
Published: 2026-07-01
Last updated: 2026-07-01
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-54900

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-549000.25% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 17% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-54900	coverage & exploitation status	NVD · CVE.org

CVE-2026-54900: Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, when in usual mode with create_id enabled, Oj::Parser#parse is vulne

Details

Exploitation outlook

Referenced CVEs

More from NVD Recent CVEs